While Fools should generally take the opinion of Wall Street with a grain of salt, it's not a bad idea to take a closer look at particularly stock-shaking upgrades and downgrades -- just in case their reasoning behind the call makes sense.

What: Shares of LifeLock (NYSE:LOCK) initially slipped 1% today after Goldman Sachs downgraded the identity theft protection technologist from buy to neutral.

So what: Along with the downgrade, analyst Greg Dunham lowered his price target to $12.50 (from $25), representing about 17% worth of upside to yesterday's close. So while contrarian traders might be attracted to LifeLock's sharp pullback in recent months, Dunham's call could reflect a sense on Wall Street that slowing revenue growth will continue to weigh on the shares over the next year.

Now what: Goldman lowered its EPS estimates for LifeLock to $0.44 for 2014, $0.63 for 2015, and $0.78 for 2016 from $0.46, $0.71, and $0.95, respectively. "[W]e are lowering estimates (i.e., 2015 EPS falls by 11%) to reflect more conservative assumptions for churn and customer acquisition," said Dunham. "We had expected the mobile app to be a strong channel for user acquisition and see the potential for higher churn and management distractions, related to regulatory and litigation dynamics, potentially impacting execution." Of course, with LifeLock shares now off a whopping 50% from their 52-week highs and trading at a PEG of 0.9, those near-term concerns might be providing Fools with an inexpensive long-term growth opportunity. 

Brian Pacampara has no position in any stocks mentioned. The Motley Fool recommends LifeLock. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.